Media captionThis is not Sierra Leone's first lockdown, as Tulip Mazumdar reports

The authorities in Sierra Leone are enforcing a three-day lockdown to curb the spread of Ebola, with the entire population ordered to stay at home.

There is a two-hour exemption on Friday to allow Muslim prayers and a five-hour window for Christians on Sunday.

Volunteers are going door-to-door, looking for people with signs of the disease and reminding others how to stay safe.

Dozens of new cases are still being reported in Sierra Leone every week.

However, the three West African countries worst affected by Ebola - Sierra Leone, Liberia and Guinea - have seen a steep reduction in infections in recent weeks.

Journalist Umaru Fofana in Freetown says the normally bustling streets in the east end of the capital Freetown was deserted first thing in the morning, except for a few children fetching water in jerry cans.

Do lockdowns work?

By Smitha Mundasad, BBC News health reporter:

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Roadblocks have been set up to enforce the lockdown

This lockdown comes amidst some rare good news. According to official figures from the World Health Organization, there were just 33 new confirmed cases last week - the lowest number since June 2014.

But with these falling figures there is danger of growing complacency, the government says.

This is one of the main reasons behind the lockdown - volunteers will remind people how to protect themselves against a virus that is still a real threat.

They will focus their efforts on northern and western areas where some infections still come as a surprise to officials - 16% of cases last week were not known Ebola contacts.

Experts have criticised previous stay-at-homes as too heavy-handed and top-down in their approach. Concerns were raised that some people did not have access to food.

The hope is, a year after the outbreak was declared, such logistical problems have been ironed out and that this measure will bring the country closer to its goal of zero Ebola infections by April 2015 - an ambitious target that is just two weeks away.

The lockdown ends at 1800 GMT on Sunday.

This is the second time Sierra Leone has enforced a national lockdown, asking its population of about six million people to stay home.

The last one, in September, was criticised by the medical charity Medecins Sans Frontieres (MSF) which said it would force people underground and not help contain the virus.

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Volunteers are going house-to-house

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This house was found to be clear of Ebola

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Food was distributed to some of those who needed it

The nationwide lockdown was needed because "complacency has set in - people seemed to relax", the spokesperson for Sierra Leone's National Ebola Response Centre, Sidi Yahya Tunis, told the BBC's Newsday programme.

"We want to re-energise people's commitment to the fight against Ebola," he said.

Sierra Leone, Liberia and Guinea have set a target of having no new cases by the middle of next month.

The outbreak has killed more than 10,000 people in the three countries over the past year.